Questions tagged [mac-address]

A Media Access Control address (MAC address) is a unique identifier assigned to network interfaces for communications on the physical network segment.

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Why is networkd changing the MAC addresses of my bonded interfaces?

When I add the config files below into /etc/systemd/network and restart systemd-networkd, I find that the MAC addresses of bond0, eth0 and eth2 have all been changed to a single, locally administered ...
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Windows Server 2008 ARP Cache Poisioning

Recently ran into a very strange problem. Several applications were having issues communication through our F5 Load-Balancer. When we looked into it we found that the router had an incorrect ARP and ...
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Can ISC-DHCP bind to Option 82 rather than Mac Addresses?

We use option 82 information to limit leases presently in ISC-DHCP using a spawn with statement for our billing subclass. This keeps a single household/business from obtaining more leases than they ...
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Filtering traffic by MAC address with nftables

TL;DR: when spoofing MAC addresses, how can I make sure the real addresses won't be leaked to the rest of the network using nftables ? Context For network security training purposes I am currently ...
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How to solve Event IDs 16945 in the System logs Hyper-V MAC conflicts

After 3 years of running perfectly with Hyper-V I am all of a sudden having network problems with Hyper-V on win 2012 R2. I set up my servers 3 years ago and never had these problem until this week. ...
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How to find a server connected on network?

earlier this week we physically installed a machine in our server rack and connected it to our network switch. It has Scientific linux installed but we don't have a user account set up to log into. We ...
James Yoe's user avatar
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790 views

Keepalived failover not working for Static NAT target behind Cisco ASA

I've got a Cisco ASA[0] with a pair of Linux boxes in the DMZ running Keepalived and HAproxy acting as a load-balancing failover pair for another pair of Windows servers, also in the DMZ. I'm ...
Jamie MacIsaac's user avatar
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dhcpd.conf rule-based mapping

We have ~100 physical nodes which can host a large number of VMs apiece. We need to set up dhcpd on one machine to distribute addresses in a predictable fashion based on MAC address. We'd like to go ...
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Blocking all trafic except legitimate router

In the business centre where I work, all clients are on the same network. The Internet <--> building router <--> building network (including rogue DHCP, etc) <--> my router's WAN ...
Andy Preston's user avatar
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Filtering traffic by MAC - nftables

TL:DR : I am building a network tap with a raspberry-pi that must remains stealth. I have a bridge (br0) between the switch interface (eth0) and the workstation (eth1). Here is how i am building it (...
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Same VIP different MAC

I am observing this behavior on a dual-homed server that is sending traffic in active/active mode on its 2 links connected to the same uplink switch. The server is running IPMP so it generates traffic ...
gaetano's user avatar
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ISC DHCP assign pool/subnet to certain MAC addresses

Hej, desperate here! I'm running isc-dhcp-server 4.1 here (with webmin but that's another topic) and want to give some options (tftp-server and bootfile) to network-components that I can identify by ...
Jeremiah's user avatar
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How does VXLAN prevent duplicate MAC addresses?

It seems to me that VXLAN network identifier(VNI) works silimar to a prefix keeping identical MAC addresses on different VXLAN segments separate, so that they can coexist without duplication issues. ...
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Hyper V External Switch MAC Address Spoofing

I am trying to replace a layer 2 VPN physical server with a Hyper V virtual machine, but it doesn't look like packets are making it out of the virtual server. Does Hyper V stop spoofed MAC address ...
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Is it possible to create a second network device with a specific name?

Due to a licence server requirement I need to have an eth0 or eth1 named network device. However, my current configuration only has a network device named enp8s0. I am using a CentOS 7 linux system. ...
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"match hardware" in dhcpd.conf not working

I've been trying to get mac addresses with a certain OUI into a certain address pool. I haven't been able to get it to work at all. Here is a snippet of my dhcpd.conf and how it's applied. class "...
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Netgear Prosafe SRX5308 config with Virgin Superhub

We have just bought a Netgear Prosafe SRX5308 to provide load balancing with our 4 internet connections, but I am struggling to get it configured with our Virgin Media connection. The auto-detect ...
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Changing source MAC address of routed packets

I have linux box with one network interface and IP forwarding enabled. Let's say my IP address is 192.168.1.1 and MAC is 11:11:11:11:11:11. When a packet which is not targeted for my host arrives, it ...
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burnt Switches connected directly to the internet

We got a setup with a switch between the cable modem/bridge and the two router ports. We burn this switch every 6 months, and it has to be replaced. Symptoms are heavy packet loss or in general very ...
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Redirect traffic on port 80 into apache for unknown macs, and into squid for some macs

I have a linux box behaving like a router that handles two network interfaces: eth0 for internet and eth1 for LAN. I set up iptables in order to redirect all the web traffic coming by the LAN into a ...
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Softether VPN Client - vpncmd - Two different MAC addresses for one virtual interface

I've encountered strange MAC behaviour in my system - I've got 15 Linux Ubuntu machines with NetworkManager disabled and dhcpcd as DHCP client. Those devices connect to my SoftEther virtual HUB and as ...
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How to find HA interface mac address in Fortigate?

We have two Fortinet and HA them. In "primary" I can see the Mac address for all interfaces easily in Network -> Interfaces -> Edit Interface. but I can't find the Mac address for &...
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network does not work for VM after a while, only resolves after changing MAC

I have installed pfSense as a KVM guest in a Debian 11 host using libvirt. The host has two interfaces. One is attached to the VM using macVLAN driver, and serves as pfSense's WAN interface. The other ...
Mustafa Mohiuodin's user avatar
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netplan mac address matching doesn't seem to work

I have a small pc box that only have one network interface, and since I needed 2 more interfaces, I've bought two usb network cards. Both same manufacturer. I wanted to rename interfaces (since they ...
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Router forces to use netcard's hardware mac

I'm trying to connect to a network that manages device connections by it's mac. So, I want to connect a device, which has no interface to connect it properly by itself I decided to use a different ...
Undermouse's user avatar
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TAP interface generating same MAC address on multiple servers

We use PeeerVPN on Debian 11 servers and we recognized that the TAP interfaces on multiple servers comes up with the same MAC address (it should be random generated). Is anyone experienced the same ...
Arany Péter's user avatar
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dnsmasq: Change DHCP range based on group of MAC address

Is it possible to change the DHCP range dnsmasq gives out based on the MAC address block. For example, I want all MACs in the block 00:0C:29 to have a different DHCP range compared to every device on ...
foxtdev's user avatar
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Mac address flapping during VM migration in WSFC

I am trying to troubleshoot an issue with our servers on a customer network. We do not support the network infrastructure. For example, I have 2 nodes(WS2019) in the Failover Cluster. Each NODE have 2 ...
Andro Leo's user avatar
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Why is the mac address that appears on my computer the same?

I use the 2 ethernet interface on the my system board, eth0 / eth1(usb to ethernet) like the followings. root@E3-RDP:~# ifconfig eth0 Link encap:Ethernet HWaddr ae:a1:99:48:86:79 inet addr:10.10.0....
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Get information about MAC address

My router (FritzBox 7330) shows tons of errors about a device that continuously try to connect to my network: 23.12.19 10:17:07 Registrazione del dispositivo wireless fallita: chiave wireless ...
Mark's user avatar
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How to use my router's Mac Address on Pfsense installed on Esxi

My ISP bind my router's Mac address so only this router can connect to their pppoe server, now I want to connect it on Pfsense installed on Esxi for better configuration options but pppoe server is ...
Uzair Ali's user avatar
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Getting a static MAC address on AWS EC2

I want to ensure that my AWS EC2 instance has a static MAC address (for an app that ties the license to the MAC address). From what I read I just need to add an ENI to the instance to get a static ...
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Get mac address based on ip in filter wireshark

i am a test engineer writing some test cases. I am trying to write a test which has to be performed in wireshark. However, my collegues aren't that "into wireshark" and i would like to keep it as ...
tomvda's user avatar
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Is it possible to isolate a network device from the rest of the LAN via its MAC address ?

Is it possible to isolate a network device from the rest of the LAN via its MAC address ? Im familiar with creating a VLAN based on a tagged port of the network switch, but is it possible by ...
sam's user avatar
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1 answer
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Mac address not entering mac table of a huawei s5700 switch

We have a very strange problem, where certain ports refuse to learn the mac addresses of their hosts. For example host A is connected to switch S1 on port 0/0/30. Each packet to host A results in a ...
Alexander's user avatar
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Windows Server 2012 DHCP Failover and MAC address replication

I'm stuck with a problem in my configuration. We have a domain controller who works also as DNS and DHCP server. Yesterday i deployed a secondary DHCP server and configured it in a failover cluster ...
Mattia Tupone's user avatar
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Why are there different types of bond configuration policies in linux, instead of one that can give a combined throughput and fail-over configuration?

I am confused and not able to understand exactly the actual concept behind it. At switch level, what happens that prevents to use one globally accepted bond configuration policy? And I don't ...
GP92's user avatar
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No network after MAC address change

I'm running a CentOS 5.4 box for which I need to spoof a MAC address in order to make a certain software work (nothing illegal going on, before you ask). Problem: Whenever I try to change the MAC, I ...
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arp table contains addresses asigned to 00:00:00:00:00:00 mac address

What mean 00:00:00:00:00:00 MAC address in arp table? On my OpenWRT router on interface connected to ISP I have seen 24 entries with this MAC address and on local network there are 7 entries. What ...
Misaz's user avatar
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Spacewalk/Cobbler system with multiple interfaces/MAC

I have bare metal provisioning set up with a DHCP/PXE server and a Spacewalk server. I'm using cobbler system records to match a machines MAC address to the system profile. Basically: cobbler ...
ryan8v's user avatar
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1 answer
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Packetfence & Aruba

I have a fresh install of a PacketFence (PF) server. Also, I have an Aruba networks AccessPoint (API-205), which I am using to send the users to the Captive Portal in PF. But the captive portal ...
Zimpari's user avatar
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Cannot find a device attached to network

My work has a wireless alarm system installed, and we recently got a wireless camera to add to it (made by the same company, it simply plug-n-plays). The alarm system uses a small router like device ...
Mr Pablo's user avatar
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Spoofing a duplicate MAC address on an interface not connecting to the network where the original MAC is

I'm trying to run a PHP project on a test server. The project uses an internal framework that has been modified so it will only run on the production server by checking the MAC address in eth0, and ...
Snivs's user avatar
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1 answer
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calculate reserved ip address based on mac address

Is it possible to calculate ip address based on mac address for isc-dhcp server? For example: 'aa:aa:aa:aa:aa:x' => '10.10.10.x' I have following in dhcpd.conf: subnet 10.10.10.0 netmask 255.255....
kakabomba's user avatar
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Polycom VOIP phone seems to mask the secondary device's MAC address from a Cisco switch

When I have a Polycom VOIP phone plugged into a Cisco switch and a laptop plugged into the Polycom phone I get the following. 1) The phone goes into the voice VLAN as expected. 2) The laptop goes ...
Boris Epstein's user avatar
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1 answer
1k views

MAC ID Binding to IP on Windows

Is there a way i can bind a certain IP to have traffic allowed if it has a certain MAC ID on windows routing and remote access or network policies? Basically Associated MAC ID to IP xxx.xxx.xxx.xxx ...
soniccool's user avatar
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Wireless Client missing from MAC table

I am currently having problems with Wireless Clients loosing network connectivity, though still displaying a connection to their Wireless Access Point. I have 4 Wireless APs, each a Cisco WAP321 ...
Jamie's user avatar
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Do some network administrators assign MAC addresses with an unassigned OUI?

I am in a situation where I have observed MAC addresses on a network that do not belong to any assigned OUI range, and this is causing some issues. I suspect the cause here is a heavy use of ...
Fred Thomsen's user avatar
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Network access sometimes lost, disabling port security temporary solves?

I have network based primarily on Edge-Core managed switched. Port security with max mac count = 1 is enabled, DHCP snoopping enabled. Some clients have troubles with accesing network, but when I ...
josefus's user avatar
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Does the IP -> Ethernet multicast address mapping ambiguity matter for IGMP snooping switches?

There are 2^28 possible IP multicast addresses, but only 2^23 possible Ethernet (MAC) multicast addresses (http://technet.microsoft.com/en-us/library/cc957928.aspx), which is why e.g. 224.1.1.1 gets ...
Evgeniy Berezovsky's user avatar